JP6923200B2 - Bending machine - Google Patents

Description

The present invention relates to a bending apparatus used when deforming a metal tube.

There are various types of tubes for flowing liquids and gases depending on the application, but most of them are sold in a straight line. However, the pipe is often used in a bent state, and in that case, the builder or the like bends the pipe by various means. If it is a thin metal pipe, bending can be performed by a manual pipe bender or the like, but since the productivity is poor manually, some kind of processing equipment is required when bending a large number of pipes. Moreover, when bending a thick metal pipe, a processing device is indispensable.

Various technological developments have been made so far regarding the bending process of metal pipes and the like, and the patent document described later is given as an example. Among them, Patent Document 1 discloses a pipe bending machine using a power press, and by performing bending with a general-purpose power press without using a dedicated processing machine, cost reduction and productivity improvement are realized. ing. This processing machine has a structure in which a pipe is sandwiched between a lower mold and an upper mold, and the lower mold is divided into three elements, a lower middle mold that can move up and down and a rotatable lower outer mold. Then, as the upper mold descends, the lower middle mold is pressed to pressurize the cushion rubber underneath, and the lower outer mold rotates so as to pop up, finishing the pipe into an appropriate bent shape. After processing, the elasticity of the cushion rubber causes the pipe to pop out naturally.

Patent Document 2 discloses a method for manufacturing an arm member. The arm member is made by joining joints to both ends of the member body using a hollow pipe material and bending the member body into a U shape by press working. To bend the member body, use a punch and a receiving die. I am using it. The punch is U-shaped, and the receiving die is provided with a molding recess. By lowering the punch, the member body is pushed into the molding recess and adjusted to a predetermined shape. Further, it is disclosed that a pressing die is provided in consideration of springback during press working.

Patent Document 3 discloses a bending apparatus for a pipe material or the like. This device has a structure in which a pair of receivers are provided in a receiver, the center of the pipe material supported by the receivers is pushed by a pressing ram, and the pipe material is bent. Further, it has a function of rotating the receiver and pressing the parallel portions at both ends of the pipe material inward so as to absorb the springback portion of the pipe material. In order to rotate the receiver, the receiver and the base on which the receiver is placed are divided into two parts, and the top of the bent pipe material presses the receiver to rotate the base, and the receiver placed on the base. The child also rotates integrally.

Japanese Unexamined Patent Publication No. 50-103463 Japanese Unexamined Patent Publication No. 2000-176581 Utility Model Registration No. 32055593

An example of the use of a bent metal pipe is road heating, in which hot water is allowed to flow underground and the heat melts ice and snow. This method has advantages such as the road surface not getting wet, but in the construction, since the metal pipes through which hot water flows are laid in a zigzag shape at narrow intervals, a large number of metal pipes bent in a U shape are required. However, if bent metal pipes are procured from the outside, the purchase price will be high due to the balance between supply and demand, and the construction price will inevitably rise, which will hinder the spread of this method of road heating. ing. Therefore, it is considered that the contractor owns the processing equipment and bends it at low cost, but even in that case, it has high processing accuracy so as not to obstruct the flow of hot water, and the construction work on site is smooth. It is desirable to be able to do it.

The present invention has been developed based on such circumstances, and an object of the present invention is to provide a bending apparatus capable of deforming a metal tube at low cost and with high accuracy.

In the invention according to claim 1 for solving the above-mentioned problems, a metal pipe arranged substantially horizontally is sandwiched between contact surfaces of an upper mold and a lower mold, and an intermediate portion of the metal pipe is pushed downward to be deformed. In the bending device, an accommodating groove for fitting the upper half of the metal pipe is provided on the upper mold side of the contact surface, and the lower half of the metal pipe is fitted on the lower mold side of the contact surface. A storage groove is provided, the metal pipe is deformed along the contact surface, the upper mold can be moved in the vertical direction by a hydraulic cylinder or the like, and the lower mold is located in the center of the fixed mold located on the left and right. It is divided into three elements with a movable mold located, the fixed mold is fixed to a frame, and the movable mold is movable in the vertical direction with respect to the frame, and usually the movable mold is referred to as the movable mold. It is arranged above the fixed mold, and a pair of pressing bodies on which the metal tube before deformation is placed is arranged on the outer side of the upper part of the fixed mold, and the pressing bodies rotate with respect to the frame. It is freely attached, and the pressing body and the movable mold are connected by a link, and when the movable mold moves downward, the pressing body moves inward through the link and the upper mold descends. By doing so, the central portion of the metal pipe is pushed downward, and at the same time, both ends of the metal pipe rise up, and when the upper mold pushes the movable mold, the pressing body moves, and the metal pipe It is a bending device characterized by pushing both ends inward.

The bending apparatus according to the present invention is used to deform a metal pipe that extends straight, and has a structure in which an intermediate portion excluding both ends of the metal pipe is pushed by an upper mold and brought into close contact with the lower mold. The metal pipe before processing is arranged almost horizontally, but the upper mold is arranged above the metal pipe, the lower mold is arranged below the metal pipe, and the contact surface between the upper mold and the lower mold is made of metal. Insert the tube. Therefore, when this contact surface is viewed from the side surface of the device, the central portion extends so as to project downward, and the metal tube is deformed along the contact surface. As a general rule, the metal tube has a hollow circular cross section, but if various conditions are met, it can be used for non-hollow ones and also for other than circular cross sections.

A storage groove for fitting a metal tube is provided on the contact surface between the upper mold and the lower mold. Since the accommodating grooves are provided in both the upper mold and the lower mold, the accommodating grooves formed in the individual molds are substantially symmetrical with respect to the contact surface. In the present invention, since the entire section of the total length of the metal pipe that causes deformation is sandwiched between the upper mold and the lower mold, deformation of the cross section thereof is regulated, the original shape can be maintained, and defects such as crushing are prevented. The upper mold can be moved up and down with a hydraulic cylinder, etc., while the lower mold is attached to a frame that is placed on the floor.

The lower mold has a hollowed-out shape at the upper center, but it is not an integral structure, but is divided into three elements: a movable mold located in the center and a fixed mold located on the left and right, of which only the fixed mold is used. It is integrated with the frame. On the other hand, the movable type is movable in the vertical direction with respect to the frame. A spring or the like is built into the movable type, and it is always placed above the fixed type. Then, when the upper mold is lowered and the movable mold is pushed in, the movable mold is lined up with the adjacent fixed mold without a step, and the accommodating groove of the entire lower mold is also lined up without a step.

The pressing body is paired at two places on the left and right, and in addition to placing both ends of the metal tube before deformation, it also has the role of pushing both ends of the metal tube inward at the final stage of deformation in consideration of the springback of the metal tube. Carry. Therefore, the pressing body is arranged above the lower mold and outside the fixed mold in order to secure a space through which the upper mold can pass. However, the pressing body is not fixed to the frame, but is rotatably attached to the frame and moved inward at the final stage of the bending process to push both ends of the metal tube. In an actual device, the pressing body is attached to the frame via a part such as an arm.

The link is a rod-shaped part that connects the movable mold and the pressing body, and is incorporated so that the pressing body moves inward as the movable mold moves downward. The movable mold is pushed downward by contact with the upper mold, and at that time, the pressing body is moved inward by the link and covers the upper portion of the lower mold. The timing at which the lower mold contacts the movable mold is the final stage of bending, and at that time, the middle part of the metal tube is sandwiched between the upper mold and the lower mold, but both ends of the metal pipe are the upper mold. It gradually turns upward without being pinched by the lower mold. Therefore, by pushing both ends of the metal tube with a pressing body and deforming it more than it should be, the influence of the subsequent springback is eliminated.

The specific structure of the movable type and the pressing body can be freely determined, and the pressing body may be attached to the frame via the arm as described above. In that case, one end of the link may be attached to the arm instead of the pressing body. Further, in order to realize smooth movement of the link, both ends of the link are attached to a movable type or a pressing body via a pin or the like. Further, since the pushing amount is changed according to the characteristics of the metal tube, it is desirable that the length of the link can be adjusted. In addition, in order to regulate the movable range of the movable type and the pressing body, a stopper or the like is installed as necessary.

At the time of processing, first raise the upper mold to move it away from the pressing body, then place a metal tube on the pair of pressing bodies, and gradually lower the upper mold, the central part of the upper mold comes into contact with the metal tube. In the upper mold, the central part of the metal tube is pushed down and deformed into a V shape, and both ends on the pressing body gradually rise, and eventually the metal tube comes into contact with the movable mold. At that time, since the central portion of the metal pipe is completely sandwiched between the upper mold and the movable mold, deformation such as crushing is restricted, and the original cross section is maintained.

After that, when the upper mold is further lowered, the pressing body moves inward via the link, and the metal tube is fitted into the fixed mold and deformed along the contact surface between the upper mold and the lower mold. At that time, since the metal pipe is sandwiched between the upper mold and the lower mold, the entire section thereof maintains the original cross section. Further, when the upper mold pushes down the movable mold, both ends of the metal tube are pushed inward by the pressing body and are deformed more than originally intended. However, the metal tube taken out from the device is released from the restraint by the mold and springs back, so that the extra deformation is eliminated and the metal tube is finished in a regular shape. The specific value of the springback differs depending on the characteristics of the metal tube. Therefore, in reality, it is provided with a function to adjust the length of the link, etc., so that the metal tube is finished in a regular shape in all situations.

In this way, by providing an accommodating groove on the contact surface between the upper mold and the lower mold and sandwiching the metal pipe therethrough, the upper mold and the lower mold come into contact at the final stage of the bending process, and the total length of the metal pipe is covered by the accommodating groove. The entire section that causes deformation fits inside the accommodating groove. Therefore, the metal pipe is restricted from being deformed so as to protrude from the upper mold and the lower mold, and defects such as crushing can be prevented. In addition, by moving the pressing body via the link and pushing both ends of the metal tube inward, the spring back after processing finishes it in a regular shape, and it can be used immediately.

The pressing body has both the function of placing the metal tube before deformation and the function of pushing both ends of the metal tube inward, and the pressing body uses movable movement for exclusive use. No power source is required. Moreover, since the link is a simple rod shape, the mechanism for pushing both ends of the metal tube is simple and lightweight, and these features simplify the device configuration, reduce the price, and reduce the bending diameter of the metal tube. Even if it is large, it can be handled reasonably by simply extending the extension of the link. In addition, since the movable type comes into contact with the metal pipe in the middle of the bending process, the metal pipe is sandwiched between the upper mold and the lower mold at an early stage, and stable deformation is realized.

The invention according to claim 2 is for preventing improper deformation of the cross section of the metal pipe, and the accommodation groove of the upper mold has a size of accommodating a range exceeding half of the cross section of the metal pipe. It is a feature. In the invention according to claim 2, the accommodating grooves of the upper die and the lower die are not symmetrical, but the upper die has a size capable of accommodating more than half of the cross section of the metal pipe. As a result, the accommodating groove of the lower die becomes smaller, and the upper and lower accommodating grooves do not become symmetrical with respect to the contact surface, and the upper die becomes a larger asymmetrical shape. By enlarging the accommodating groove of the upper die in this way, when the metal tube is fitted only in the upper die, its deformation can be tightly regulated, and defects such as crushing are less likely to occur.

The invention according to claim 3 relates to the structure of an upper mold or a lower mold. The upper mold has a configuration in which a plurality of subdivided divided upper molds are arranged along the longitudinal direction of the contact surface, and the lower mold is subdivided. It is characterized in that a plurality of the divided lower dies are arranged along the longitudinal direction of the contact surface.

The invention according to claim 3 is characterized in that both the upper mold and the lower mold use a split mold that is subdivided with respect to the longitudinal direction of the contact surface, and each split mold is provided on one side of a metal plate. The shape is cut out from the accommodating groove. Then, by arranging a plurality of dividing dies along the longitudinal direction of the contact surface, one upper die or lower die is completed. The thickness of each divided mold is sufficiently smaller than the bending diameter of the metal pipe, and the accommodating groove formed therein does not need to consider the bending diameter of the metal pipe. Therefore, the split mold has a simple shape in which the accommodating groove is cut out on one side of the metal plate, and the manufacturing cost can be reduced as compared with the massive mold. Further, by making it possible to replace the individual division type, the maintenance of the device becomes easy.

As in the invention of claim 1, by providing an accommodating groove on the contact surface between the upper die and the lower die and sandwiching the metal pipe therefor, the upper die and the lower die come into contact with each other at the final stage of the bending process, and the metal Of the total length of the pipe, the entire section that causes deformation fits inside the accommodating groove. Therefore, deformation of the metal pipe that protrudes from the upper and lower molds is regulated, defects such as crushing can be prevented, the initial cross section is maintained over the entire length of the metal pipe, and a metal pipe with excellent accuracy is manufactured. can do. In particular, the movable type comes into contact with the metal pipe in the middle of the bending process, so that the metal pipe is sandwiched between the upper mold and the lower mold at an early stage, and stable deformation is realized.

In addition, by moving the pressing body via the link and pushing both ends of the metal tube inward, the springback after processing finishes the regular shape, and the metal tube can be used immediately without any adjustment later. become. Moreover, the pressing body also has a function of mounting the metal tube before deformation, and the movement of the pressing body is realized by transmitting the movable movement with a link, so that a dedicated power source is not required. In addition, the technology corresponding to springback has existed conventionally. However, in the present invention, by using a simple rod-shaped link, the device configuration can be simplified, the price can be suppressed, the metal tube can be bent at low cost, and even if the bending diameter of the metal tube is large, the link can be used. It can be dealt with reasonably just by extending the extension of, and the related parts will not become large.

As in the invention of claim 2, the upper mold accommodating groove is sized to accommodate a range exceeding half of the cross section of the metal pipe, so that the metal pipe is fitted into the upper mold and then the metal pipe is accommodated. Since it can constrain a range larger than half of the cross section of the pipe, its deformation is tightly regulated, preventing crushing deformation until the metal tube contacts the lower mold, and maintaining the original cross section shape. do.

As in the invention of claim 3, the upper mold and the lower mold are subdivided upper molds and lower split molds, and a plurality of these are arranged along the longitudinal direction of the contact surface. The individual upper division mold and lower division mold have a simple shape in which a storage groove is cut out on one side of the metal plate. Therefore, it is possible to manufacture a split upper mold and a split lower mold simply by cutting out a metal plate with a laser processing machine, etc., and when these are assembled, the upper mold and lower mold are completed, and there is no need to prepare an expensive dedicated mold. The manufacturing price of the device can be suppressed.

In a perspective view showing a configuration example of a bending apparatus according to the present invention, a metal tube is sandwiched between an upper die and a lower die and deformed into a U shape. It is a perspective view which shows the state which put the metal tube on the bending apparatus of FIG. After FIG. 2, it is a perspective view showing a state in which the hydraulic cylinder is operated and the metal pipe is started to be pushed in by the upper die. After FIG. 3, it is a perspective view showing a state in which the upper die is in contact with the movable die. After FIG. 4, it is a perspective view which shows the final stage which the upper die and the lower die came into contact with each other. It is a perspective view which shows the structure which made it possible to adjust the position of a pressing body with respect to an arm. In the perspective view and the vertical cross-sectional view showing the configuration examples of the upper mold and the lower mold, the upper mold is an arrangement of a plurality of divided upper molds, and the lower mold is an arrangement of a plurality of divided lower molds. Further, as shown in the vertical cross-sectional view, the maximum diameter portion of the accommodating groove is unevenly arranged toward the split upper die. It is a perspective view which shows the case where the auxiliary mold is used in order to bend a metal tube appropriately in an initial stage. It is a perspective view which shows the case where the metal tube bent in a U shape is used for road heating.

FIG. 1 shows a configuration example of a bending apparatus according to the present invention, in which a metal tube P is sandwiched between an upper die 11 and a lower die 21 and deformed into a U shape. The upper die 11 of this device has an arc shape protruding downward, and its outer peripheral surface becomes a contact surface 15 with the lower die 21, and the upper half of the metal tube P is provided at the center of the contact surface 15 over the entire length. A storage groove 16 for fitting is provided. Further, the lower mold 21 is paired with the upper mold 11, and the upper surface thereof is a contact surface 25 with the upper mold 11, and the contact surface 25 is a semicircular shape protruding downward when viewed from the side surface of the device. Further, the lower mold 21 is divided into three elements, a fixed mold 23 located on both the left and right sides and a movable mold 24 located in the center.

The upper mold 11 can be moved in the vertical direction by the hydraulic cylinder 14, and the rod 17 extending from the hydraulic cylinder 14 is connected to the upper mold 11 via the connector 18. Further, the fixed mold 23 of the lower mold 21 is fixed to the frame 41. The frame 41 is a component that serves as a base for the bending apparatus according to the present invention, and is placed on the floor surface. The fixed mold 23 in the figure has a shape similar to a right triangle, and the two sides forming the right angle portion are in contact with the frame 41. The shape of the frame 41 can be freely determined, and the method of attaching the frame 41 and the fixed mold 23 can also be freely determined. In addition, in an actual device, since the hydraulic cylinder 14 is attached, a pillar or the like is also required separately.

The movable mold 24 forming the central portion of the lower mold 21 can move in the vertical direction within a certain range with respect to the frame 41, and is usually arranged above the fixed mold 23 by a push-up tool 46 such as a spring. be. A pedestal 42 is provided under the movable type 24 in order to realize smooth movement of the movable type 24, and a stopper 47 is provided on the frame 41 in order to limit the moving range of the movable type 24. The stopper 47 functions when the fixed mold 23 and the movable mold 24 are lined up without a step, and prevents the stopper 47 from descending further.

Pressing bodies 36 on which the metal tube P is placed are arranged on the upper left and right sides of the frame 41. The pressing body 36 has a drum shape with a constricted center in order to prevent the metal tube P from rolling, and the pressing body 36 is attached to the frame 41 via arms 33 arranged on both sides thereof. The arm 33 can rotate about the fulcrum pin 32, and a block 31 for holding the fulcrum pin 32 is provided on the upper surface of the frame 41. An upper pin 35 is inserted into the center of the pressing body 36, and both ends of the upper pin 35 are held near the tip of the arm 33.

The pressing body 36 is normally located above the block 31. Therefore, a stopper 43 is provided to prevent the pressing body 36 from falling. The stopper 43 extends from the frame 41 and comes into contact with the vicinity of the middle of the arm 33 to limit its movement range. Even when the metal tube P mounted on the pressing body 36 is pushed by the upper die 11, the pressing body 36 is pushed. It will not fall.

The movable mold 24 and the pressing body 36 are connected by a link 34, and as the movable mold 24 descends, the pressing body 36 moves inward. The link 34 has a simple rod shape, the lower end thereof is attached to the lower pin 45 penetrating the pedestal 42 on which the movable type 24 is placed, and the upper end portion of the link 34 is attached to the upper pin 35 inserted in the center of the pressing body 36. The upper pin 35 is pulled downward by the lowering of the lower pin 45, but the arm 33 rotates in consideration of the fulcrum pin 32, and the pressing body 36 moves inward. The links 34 are arranged on the left and right sides of the pressing body 36 in consideration of balance, and both ends of the link 34 can be freely rotated with respect to the lower pin 45 and the upper pin 35.

When actually bending the metal pipe P, the metal pipe P is first placed so as to straddle the left and right pressing bodies 36, and then the rod 17 of the hydraulic cylinder 14 is gradually projected, so that the central portion of the upper mold 11 is formed. Contact the metal tube P. After that, the metal tube P mounted on the pressing body 36 is deformed into a V shape only by the upper die 11, but eventually the metal tube P comes into contact with the movable die 24, and the central portion of the metal tube P is raised. It is sandwiched between the mold 11 and the movable mold 24 to prevent its collapse. When the upper die 11 is subsequently lowered, the intermediate portion of the metal tube P is sandwiched between the upper die 11 and the lower die 21 without loosening, and both ends of the metal tube P are inside by the pressing body 36 so as to absorb the springback. Pushed in the direction.

FIG. 2 shows a state in which the metal tube P is placed on the bending apparatus of FIG. The metal tube P before processing is a straight line cut to a predetermined length, and both ends thereof are placed on the left and right pressing bodies 36. The center of the pressing body 36 is constricted in a drum shape, the heights of the left and right pressing bodies 36 are the same, and the metal tube P is stably stationary. The arm 33 that supports the pressing body 36 is in contact with the stopper 43, so that the pressing body 36 does not fall further. In addition, the rod 17 of the hydraulic cylinder 14 is completely retracted, and the upper die 11 is located above the metal pipe P.

FIG. 3 shows a state in which the hydraulic cylinder 14 is operated after FIG. 2 and the metal pipe P is started to be pushed by the upper die 11. When the hydraulic cylinder 14 is operated and the rod 17 is gradually projected, the lowermost portion of the upper die 11 comes into contact with the central portion of the metal pipe P, and the metal pipe P is deformed into a V shape. At that time, the upper half of the metal tube P is fitted into the accommodating groove 16 of the upper die 11, the central portion of the metal tube P is gradually deformed, and both ends of the metal tube P are gradually upright.

When the upper mold 11 comes into contact with the metal tube P, a downward load acts on the pressing body 36. At that time, the pressing body 36 tries to move outward due to the positional relationship between the fulcrum pin 32 and the upper pin 35, but the arm 33 supporting the pressing body 36 is in contact with the stopper 43, and the pressing body 36 cannot move. Is. Therefore, the downward load transmitted from the upper die 11 via the metal tube P and the pressing body 36 is received by the stopper 43, and the metal tube P is deformed only by the upper die 11 and the pressing body 36. Mold 21 is not functioning.

FIG. 4 shows a state in which the upper die 11 is in contact with the movable die 24 after FIG. The lower mold 21 is divided into three elements, a fixed mold 23 on the left and right and a movable mold 24 in the center. Among them, the movable mold 24 is arranged above the fixed mold 23, and the upper mold 11 is located at an early stage. Contact with. Therefore, the central portion of the metal tube P is sandwiched between the upper die 11 and the movable die 24 in the middle of the bending process, and the deformation that protrudes from both the accommodating grooves 16 and 26 is restricted, and the original circular cross section is maintained. At this stage, the push-up tool 46 is adjusted to generate a corresponding reaction force so that the movable type 24 can regulate the deformation of the metal tube P.

In the state shown in FIG. 4, both ends of the metal tube P are pushed by the upper die 11 to fit into the fixed die 23 and are bent upward. Therefore, both ends of the metal tube P are separated from the pressing body 36. At that stage, the metal tube P becomes U-shaped, but when the metal tube P is removed from the device, both ends open in a V-shape due to springback. Both ends of the metal tube P are not sandwiched between the upper die 11 and the lower die 21 until the end. Therefore, the processed metal tube P has a U shape instead of a semicircular shape.

FIG. 5 shows the final stage of contact between the upper die 11 and the lower die 21 after FIG. The upper die 11 pushes in the movable die 24, the upper die 11 and the lower die 21 are in complete contact, and the intermediate portion of the metal tube P is sandwiched between the accommodating grooves 16 and 26 of the upper die 11 and the lower die 21. Further, by moving the movable type 24, the link 34 pulls the upper pin 35 to rotate the arm 33, and the pressing body 36 is moved inward. As a result, both ends of the metal tube P are pushed inward by the pressing body 36 to form a worship shape. However, when the metal tube P is taken out of the device, both ends thereof are opened outward by springback and are aligned in parallel. It is known that the springback occurs not only at both ends of the metal tube P but also at the intermediate portion sandwiched between the upper die 11 and the lower die 21. Therefore, the contact surfaces 15 and 25 between the upper die 11 and the lower die 21 have a slightly smaller diameter than the actual bending diameter.

The movable type 24 can move in the vertical direction with respect to the frame 41, but when the pedestal 42 on which the movable type 24 is placed comes into contact with the stopper 47, the movable type 24 does not descend further from there. The stopper 47 functions when the movable type 24 is lined up with the fixed type 23 without a step. Further, as the pedestal 42 is lowered, the push-up tool 46 is compressed. In addition, since the pressing body 36 is also involved in the deformation of the metal tube P, the lower pin 45, the link 34, the upper pin 35, the arm 33, and the like around the pressing body 36 need to have sufficient strength, and the link 34 is balanced. It is arranged on both the left and right sides in consideration of.

Although the metal pipe P having a circular cross section is used in FIGS. 1 to 5, the metal pipe P having various cross sections can be supported by adjusting the shapes of the accommodating grooves 16 and 26 of the upper die 11 and the lower die 21. It is possible. Further, a bar material that is not hollow can be similarly deformed. In addition, in FIGS. 1 to 5, the metal tube is deformed into a U shape, but it can be deformed into another shape by exchanging the upper die 11 and the lower die 21. However, even in that case, both ends of the metal tube P are deformed by the pressing body 36.

FIG. 6 shows a structure in which the position of the pressing body 36 can be adjusted with respect to the arm 33. As shown in FIG. 5, in the final stage of deformation, the pressing body 36 pushes both ends of the metal tube P, and the pushing amount is determined by various factors such as the bending diameter, the diameter and wall thickness of the metal tube P, and the like. Need to be adjusted based on. Therefore, the position of the pressing body 36 with respect to the arm 33 can be adjusted so that the metal tube P can be appropriately pushed in in all situations. In FIG. 6, an elongated hole 38 is provided near the tip of the arm 33 so that the upper pin 35 can move in the elongated hole 38, and the pressing body 36 also moves integrally with the upper pin 35.

Further, in order to fix the positional relationship between the arm 33 and the pressing body 36, the clevis 51 is arranged on the outside of the arm 33. The clevis 51 is composed of a head 52 and a male screw 53, and by inserting the upper pin 35 into the head 52, the clevis 51 and the upper pin 35 are integrated. Further, the male screw 53 penetrates the branch plate 37 extending from the intermediate portion of the arm 33. Then, the nut 54 is screwed into the male screw 53, and the branch plate 37 is sandwiched between the nut 54, whereby the position of the upper pin 35 with respect to the arm 33 is fixed. Therefore, even when a large load is applied to the pressing body 36, the pressing body 36 does not move with respect to the arm 33, and the metal tube P can be reliably pushed in.

In the upper part of FIG. 6, the upper pin 35 is located above the elongated hole 38. However, when the nut 54 is loosened and the clevis 51 is moved downward, the pressing body 36 also moves downward integrally, and when the nut 54 is tightened there, the upper pin 35 is inserted into the elongated hole 38 as shown in the lower part of FIG. Can be fixed below. Actually, in addition to the position of the pressing body 36, the length of the link 34 can also be adjusted, and by adjusting these integrally, the metal tube P can be made into a regular shape even if various conditions are different. Can be finished.

FIG. 7 shows a configuration example of the upper mold 11 and the lower mold 21, in which the upper mold 11 is an arrangement of a plurality of divided upper molds 12, and the lower mold 21 is an arrangement of a plurality of divided lower molds 22. Is. The split upper die 12 and the split lower die 22 have accommodating grooves 16 and 26 formed in a hard metal plate, and a plurality of the accommodating grooves 16 and 26 are formed along the longitudinal direction of the contact surfaces 15 and 25 between the upper die 11 and the lower die 21. By arranging them side by side, one upper mold 11 and lower mold 21 are completed. The split upper mold 12 is fixed to the mounting plate 19 bent into a semicircle, and a gap is formed at the boundary between the adjacent split upper molds 12. In addition, a connector 18 for attaching the rod 17 is provided in the center of the mounting plate 19.

The lower mold 21 is divided into three elements, a fixed mold 23 on the left and right and a movable mold 24 in the center. 28 and the middle mounting base 29 are used, the side mounting base 28 becomes a fixed type 23, and the middle mounting base 29 becomes a movable type 24. The thickness of the individual split upper die 12 and the split lower die 22 is sufficiently smaller than the bending diameter of the metal tube P. Therefore, the individual accommodating grooves 16 and 26 do not need to have a two-dimensional curved surface in consideration of the bending diameter of the metal pipe P, and may be simply cut out.

In addition, as shown on the right side of FIG. 7, the accommodating grooves 16 and 26 of both the split upper die 12 and the split lower die 22 may not be arranged symmetrically with respect to the contact surfaces 15 and 25. When such a split upper mold 12 and a split lower mold 22 are brought into contact with each other, the centers of the accommodating grooves 16 and 26 are biased toward the split upper mold 12. As a result, before the metal tube P comes into contact with the lower die 21, more than half of the metal tube P is fitted into the split upper die 12, and the maximum diameter portion thereof is sandwiched by the split upper die 12, and the metal tube P is sandwiched. Deformation is regulated.

Even when the split upper die 12 and the split lower die 22 are used, the accommodating grooves 16 and 26 may be arranged symmetrically with respect to the contact surfaces 15 and 25. Further, the accommodating groove 16 of the split upper die 12 shown on the right side of FIG. 7 has a simple circular shape, but in order to smoothly fit the metal pipe P, the section below the maximum diameter portion is set as a simple vertical surface. The accommodating groove 16 may be U-shaped instead of circular.

FIG. 8 shows a case where the auxiliary mold 55 is used in order to properly bend the metal tube P in the initial stage. Normally, a series of bending processes is performed only by the upper die 11, the lower die 21, and the pressing body 36, but the central portion of the metal tube P may be excessively deformed depending on the bending diameter and the characteristics of the metal tube P. In particular, in the initial stage of the bending process, as shown in FIG. 3, since the deformation proceeds only with the upper die 11, the restraint of the metal tube P becomes insufficient, and the cross section may be significantly deformed. FIG. 8 shows an example of the countermeasure, in which the metal tube P is sandwiched between the upper die 11 and the auxiliary die 55 to suppress the deformation of the cross section.

The auxiliary mold 55 is a component incorporated into the upper mold 11 and extends horizontally without being curved, and a storage groove 56 into which the metal pipe P is fitted is provided in the center of the upper surface thereof. Further, a connecting plate 57 extending upward is attached to the center of the left and right side surfaces of the auxiliary mold 55. A massive support piece 59 is provided in the center of the upper surface of the upper mold 11, and the auxiliary mold 55 is brought close to the upper mold 11, and the support piece 59 is sandwiched between the two connecting plates 57 so as to penetrate both of them. When the bolt 58 is inserted, the auxiliary mold 55 is attached to the upper mold 11. Further, the metal pipe P can be held by the space formed by the accommodating groove 16 of the upper die 11 and the accommodating groove 56 of the auxiliary die 55.

When using the auxiliary mold 55, first, the upper mold 11 is lifted, the auxiliary mold 55 is incorporated into the upper mold 11 by using a bolt 58, and the metal pipe P is inserted into the accommodating grooves 16 and 56. Next, when the upper die 11 is lowered, both ends of the metal tube P come into contact with the pressing body 36, and the central portion thereof is gradually deformed. Prevent defects. However, the auxiliary mold 55 must not come into contact with the lower mold 21, and the auxiliary mold 55 is removed when the deformation has progressed to some extent, and thereafter, the metal tube P is sandwiched between the upper mold 11 and the lower mold 21. As an alternative to the auxiliary type 55, the movable type 24 can also be used. In that case, the moving range of the movable mold 24 is increased, and the movable mold 24 is brought into contact with the metal tube P at the stage shown in FIG. As a result, the movable type 24 has the same functions as the auxiliary type 55.

FIG. 9 shows a case where a U-shaped bent metal tube P is used for road heating. The road heating in this figure is a method of heating the road surface by flowing hot water through the metal pipe P, and since water is not sprinkled, the road surface does not get wet and the comfort of pedestrians and the like is improved. In the construction, as shown in the upper part of FIG. 9, the road surface is excavated to a certain depth in a wide range, and a digging portion lowered by one step is provided. Next, metal pipes P are laid over the entire area of the dug portion, but in order to realize uniform heating, linear metal pipes P are arranged at narrow intervals, and the ends thereof are U-shaped metal. It is connected by a tube P. Then, when the dug portion is backfilled and the road surface is improved, the metal pipe P is completely embedded as shown in the lower part of FIG.

The temperature of the hot water flowing through the metal tube P gradually decreases. Therefore, in FIG. 9, the metal pipe P immediately after water supply and the metal pipe P immediately before drainage are adjacent to each other, and the amount of heat dissipated is substantially equal over the entire area. In the road heating as shown in FIG. 9, it is desirable to use a thin metal tube P having excellent heat conduction in order to efficiently dissipate the heat of hot water to the outside. On the other hand, the resin tube is not suitable for such an application because it has a high heat insulating property and a low efficiency.

As shown in FIG. 9, in order to lay the metal pipes P at narrow intervals by road heating, a large number of U-shaped bent metal pipes P are required, and if all of them are procured from the outside, the construction price will be increased. The rise is inevitable. However, by using the bending apparatus according to the present invention, the metal pipe P can be secured by itself, so that the construction cost can be suppressed. Further, in the present invention, both ends of the metal tube P can be aligned in parallel, and it is not necessary to adjust the shape of the metal tube P on site. Therefore, the laying work can be started immediately, and the labor and time during construction can be reduced. As a matter of course, the introduction of the bending apparatus according to the present invention requires a reasonable investment, but the investment can be reasonably recovered by securing the number of construction works. Although the present invention has been developed for bending the metal tube P used in road heating, the use of the metal tube P is not limited, and the bending shape is not limited to the U shape.

11 Upper mold 12 Divided upper mold 14 Hydraulic cylinder 15 Contact surface (upper mold side)
16 Storage groove (upper mold side)
17 Rod 18 Connector 19 Mounting plate 21 Lower mold 22 Divided lower mold 23 Fixed mold 24 Movable mold 25 Contact surface (lower mold side)
26 Storage groove (lower mold side)
28 Side mount 29 Middle mount 31 Block 32 Supporting pin 33 Arm 34 Link 35 Upper pin 36 Pressing body 37 Branch plate 38 Long hole 41 Frame 42 Pedestal 43 Stopper (contact with arm)
45 Lower pin 46 Push-up tool 47 Stopper (contact with pedestal)
51 Clevis 52 Head 53 Male screw 54 Nut 55 Auxiliary type 56 Storage groove 57 Connection plate 58 Bolt 59 Support piece P Metal pipe

Claims (3)

A metal tube (P) arranged substantially horizontally is sandwiched between contact surfaces (15, 25) between the upper die (11) and the lower die (21), and the intermediate portion of the metal tube (P) is pushed downward to deform. It is a bending machine that makes
An accommodating groove (16) into which the upper half of the metal tube (P) is fitted is provided on the upper die (11) side of the contact surface (15, 25), and the lower die (15, 25) of the contact surface (15, 25) is provided. On the 21) side, an accommodating groove (26) into which the lower half of the metal tube (P) is fitted is provided, and the metal tube (P) is deformed along the contact surfaces (15, 25).
The upper mold (11) can be moved in the vertical direction by a hydraulic cylinder (14) or the like.
The lower mold (21) is divided into three elements, a fixed mold (23) located on the left and right and a movable mold (24) located in the center, and the fixed mold (23) is fixed to the frame (41). The movable mold (24) is movable in the vertical direction with respect to the frame (41), and the movable mold (24) is usually arranged above the fixed mold (23). can be,
A pair of pressing bodies (36) on which the metal tube (P) before deformation is placed are arranged on the upper outer side of the fixed mold (23), and the pressing bodies (36) are mounted on the frame (41). The pressing body (36) and the movable mold (24) are connected by a link (34), and the movable mold (24) moves downward to cause the link (24). The pressing body (36) moves inward via 34), and the pressing body (36) moves inward.
When the upper mold (11) is lowered, the central portion of the metal pipe (P) is pushed downward, and at the same time, both ends of the metal pipe (P) are raised, and the upper mold (11) is further raised. A bending apparatus characterized in that the pressing body (36) moves by pushing the movable mold (24), and both ends of the metal tube (P) are pushed inward. The bending apparatus according to claim 1, wherein the accommodating groove (16) of the upper die (11) has a size accommodating a range exceeding half of the cross section of the metal pipe (P). The upper mold (11) has a configuration in which a plurality of subdivided upper molds (12) are arranged along the longitudinal direction of the contact surface (15), and the lower mold (21) has a subdivided division. The bending apparatus according to claim 1 or 2, wherein a plurality of lower molds (22) are arranged along the longitudinal direction of the contact surface (25).

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